LAUSR

Abstract Given the possibility of short-term changes in hydrological patterns caused by climatic change, there is a need to assess the effects of inundation frequency on soil nitrogen cycling in estuarine wetland ecosystems. Here, we performed soil/plant translocation experiments in Shanyu tidal marsh, China, and examined the effects of elevated and reduced frequencies of inundation on nitrogen cycling over a period of 90 days. Our results indicated that soil ammonia levels (14.35–25.37 mg N kg−1) showed similar responses to changes in inundation frequency, whereas after 60 days of elevated inundation frequency, nitrate levels (0.32–1.52 mg N kg−1) were lower by 42.72% compared with the initial levels, although there were no significant changes in nitrate levels in response to reduced inundation frequency. After 90 days, both nitrification and denitrification rates were observed to correspond to naturally occurring hydrological gradients, showing increases of 564.49% and 108.82%, respectively, in response to elevated inundation frequency, and decreases of –77.83% and –94.92%, respectively, in response to reduced inundation frequency. Moisture, Fe(II), Fe(III), electrical conductivity, arbuscular mycorrhizal fungi, and plants were identified prominent factor contributing to the observed changes in nitrification and denitrification. Our findings highlight the likelihood of changes in nitrification and denitrification in response to short-term elevation or reduction inundation frequency.